Turmeric powder, extracts and oleoresins are some of the widely used commercial products of C. longa plant. Solvent extraction of dried turmeric rhizomes yields a mixture of three curcuminoids: curcumin (typically at a level of 90-95% purity), demethoxycurcumin and bisdemethoxycurcumin.
While curcumin and its metabolite tetrahydrocurcumin have demonstrated antioxidant, antiproliferative and antiangiogenic activities, extremely poor aqueous solubility limits the bioavailability and therapeutic effective of curcumin. Orally administered curcumin and tetrahydrocurcumin formulations have exhibited poor absorption, rapid metabolism, and rapid systemic elimination in vivo. As outlined in U.S. Patent Application Document No. 20140010903, efforts to improve the bioavailability of curcumin have included the use of adjuvants like piperine, liposomal and nanoparticulate formulations, phospholipid complexes and structural analogs.
Further examples of strategies which have been employed to improve curcumin bioavailability and solubility include (1) dispersion of curcumin in lipophilic matrix (Mereva®) (2) administering curcumin with piperine (Sabinsa) (3) combining curcumin with volatile oils of turmeric (BCM-95®), and (4) micronization and micellation of curcumin (Aquanova) [1-4].
Given curcumin's demonstrated anti-inflammatory, antioxidant, antiproliferative and antiangiogenic activities, the need exists for curcuminoid formulations which exhibit improved bioavailability and which are more readily formulated than known curcuminoid dosage forms.